The invention refers to an orderly packing for a column as well as to a mass transfer column with such a packing.
The packing is composed, for example, of layers of sheets folded in the form of waves or zigzags. The sheets consist of a foil-like material (e.g., of thin sheetmetal or fabric); the edges of the folds or the crests exhibit a direction inclined to the axis of the column, the angle included with the axis amounting, for example, to 45.degree. or 30.degree.. The layers formed by the sheets are aligned in parallel with the axis; they are arranged alternately as regards the slope of the edges of the folds, so that open channels running obliquely and crossing one another result. The packing is composed of sections which differ in the orientation of the layering. Between adjacent sections the orientation changes each time through 90.degree..
Further examples of orderly packings which cause a distribution of the two mass flows over the cross-section of the column are described in the European patent specifications 0 070 917 and 0 069 241.
At the vertical edges of the packing some of the alternately arranged layers steer the trickling film towards the edges of the sheets as it flows over the sheets, which leads to the phenomenon of an edge-seeking liquid. The practice is known of providing between the sections of packing at the wall of the column, elements like crowns which guide the edge-seeking liquid round in such a way that it partially over the layers steering it inwards--flows back again into the interior of the packing. From the U.S. Pat. No. 4,186,159 or Swiss patent 618 006 elements of that kind are known, in the form of collars which may be arranged at various heights on the sections of packing.
One individual section of packing of the mass transfer column may consist of a cohesive insert element; it may--especially in the case of a large diameter of the column--also be composed of a number of segments. In that case the packing often also exhibits in the interior, parting planes which run transversely to the layers; that is, junctions between adjacent segments. These parting planes interrupt the channels and exercise an edge effect because of which edge-seeking liquid also arises at the junctions.
For the junctions no means are known for avoiding or returning edge-seeking liquid; means of that kind for the edge of the column--such, for example, as collars--exhibit a very restricted efficiency.